1. Field of the Invention
A rail positioning device for use with a retractable bumper assembly to prevent bowling balls from entering a gutter adjacent the retractable bumper assembly.
2. Description of the Prior Art
A poorly thrown bowling ball can fall into either gutter. For various reasons bumper systems have been developed that prevent a bowling ball from entering the gutters. Generally, an elongated guard or rail is placed along the length of each gutter to prevent a bowling ball from entering the corresponding gutter.
Numerous retractable bumper systems have been developed which permit the elongated guards or rails to be easily deployed or retracted. There are several problems associated with these various systems including:                The attaching means at the pivot connection between the rail and the support members normally consist of a mechanical fastener that is exposed to view.        The pivots are rigidly mechanically attached to the rail making the pivots vulnerable to ball impact, which in turn causes damage to the pivots.        Some rail materials expand and contract with moisture and/or temperature changes. This causes undo stress on the rails and pivot arms.        Assembly is required on all the known rail pivot combinations prior to packaging and shipping which adds to the cost of shipping, labor and overhead.        Exposed fasteners sometimes come loose and cause ball damage.        Excessive ball speed impact damages rails and pivot arms that must be replaced prior additional use. Replacement is time consuming and expensive and normally involves both the rail and multiple pivot arms.        
U.S. Pat. No. 6,402,629 describes a bumper system to prevent a bowling ball from entering the gutters, redirecting the ball into the lane comprising a longitudinal rail with a plurality of pivot arms affixed thereto. The pivot arms are pivotally affixed to the lane bed such that when the bumper system is in a retracted position the horizontal surface of the longitudinal rails are in a substantially abutting relation to the side of the lane, and the adjacent gutters are adapted to receive any balls that are bowled towards either side of the lane, directing the balls to the end of the lane, missing the pin deck. In an extended position, the longitudinal rails prevent balls from entering the adjacent gutters redirecting balls into the lane such that the balls strike the pins in the pin deck.
U.S. Pat. No. 5,380,251 discloses a bowling alley bumper system to selectively guard against a bowling ball rolling into a gutter comprising a bungee cord extends along each side edge of a bowling alley lane. When the bungee cord is and in a first position below the lane surface bowling balls can roll into a gutter. A lifting mechanism can raise the bungee cord to a position above the lane surface for receiving bowling balls rolling on the surface toward the gutter and redirecting the bowling balls toward the center of the lane and away from the gutter. The bungee cord is lifted to its second position by a plurality of elongated rods positioned to move alongside the lane below the gutter surface. A connecting rod raises and lowers the elongated rods through a lever action thereby positioning the bungee cord at its first stored position or its elevated position for guarding the gutter.
Additional examples of such retractable bumper systems have been described in: U.S. Pat. No. 4,420,155; U.S. Pat. No. 4,792,136; U.S. Pat. No. 4,900,024; U.S. Pat. No. 5,181,716; U.S. Pat. No. 5,207,422; U.S. Pat. No. 5,304,097; U.S. Pat. No. 5,322,476; U.S. Pat. No. 5,358,448; U.S. Pat. No. 45,405,295; U.S. Pat. No. 5,415,591; U.S. Pat. No. 5,417,616; U.S. Pat. No. 5,435,788; U.S. Pat. No. RE. 35,232; U.S. Pat. No. 5,564,986; U.S. Pat. No. 5,681,224; U.S. Pat. No. 5,800,274 and U.S. Pat. No. 5,857,918.